In vivo detection of reactive oxygen species using turn-on luminescent probes based on IR783-modified upconversion nanoparticles

Precise regulation of endogenous reactive oxygen species (ROS) is critical for maintaining physiological homeostasis, while dysregulated ROS levels are implicated in diverse pathologies. In vivo monitoring of this key signaling molecule represents an urgent priority, yet poses significant challenges due to the limitations of conventional ROS probes reliant on ultraviolet-visible excitation for high-fidelity biological imaging. To address this constraint, we engineered a luminescent nanoprobe by conjugating IR783 with upconversion nanoparticles (UCNPs), enabling H 2 O 2 detection via upconversion luminescence. The detection mechanism involves ROS-triggered cleavage of IR783, inducing nanostructure disassembly and subsequent restoration of upconversion luminescence. This design yields a concentration-dependent luminescence turn-on response, where upconversion luminescence intensity escalates proportionally with H 2 O 2 levels. The UCNPs-IR783 nanoprobe exhibits minimal cross-reactivity with biomolecules and low cytotoxicity, enabling effective visualization of both intrinsic and extrinsic reactive oxygen species within Hepa1-6 and RAW264.7 cellular models. Furthermore, investigations in murine subjects validate its applicability for ROS detection specifically within the tumor microenvironment.